大豆磷脂对不动杆菌降解硝基苯的影响

研究了液相体系中不同用量的大豆磷脂对不动杆菌降解硝基苯的影响.大豆磷脂可以作为不动杆菌的唯一碳源,在一定程度上支持其生长.实验表明,在适宜不动杆菌生长的400 mg/L硝基苯质量浓度下,加入500 mg/L大豆磷脂对不动杆菌生物量和硝基苯的完全降解时间无影响,而加入250,1 000 mg/L大豆磷脂却延缓了细菌的生长和硝基苯的降解,这主要是由于它与硝基苯形成竞争代谢或是由于硝基苯在胶束中的分配降低了其生物可利用性;当硝基苯质量浓度约为600 mg/L时,加入大豆磷脂(高于临界胶束浓度)显著促进了细菌的生长和硝基苯的降解,并且促进效果与加入量成正比,这主要是因为胶束的分配作用对硝基苯产生了脱毒效果,另外大豆磷脂作为辅助碳源增加了生物量,也促进了对硝基苯的代谢分解. 

Influence of Soya Lecithin on the Biodegradation of Nitrobenzene by Acinetobacter sp.

The influence of soya lecithin on the biodegradation of nitrobenzene by Acinetobacter sp. in liquid cultures at different dosage was investigated.The soya lecithin can somewhat support the growth of \%Acinetobacter\% sp. as its sole carbon source.The experiments showed that when the initial nitrobenzene concentration was about 400 mg/L(relatively low for bacteria to grow vigorously),soya lecithin added at 500 mg/L had no effect on the biomass of \%Acinetobacter\% sp. and the degradation of nitrobenzene.However,it retarded bacterial growth and the time for nitrobenzenes full removal when used at 250 mg/L and 1 000 mg/L,which might result from the competitive metabolism of soya lecithin or decreased bioavailability of nitrobenzene after being partitioned into the surfactant micelle.While the initial nitrobenzene concentration was about 600 mg/L,it significantly enhanced the bacterial growth and the biodegradation if added over its critical micelle concentration,and the promoting effect was increased proportionally with the concentration of soya lecithin.It might be due to the detoxification effect of surfactant micelles and the increased biomass for soya lecithin served as additional carbon soure.